I'd like to reserve a water bender :D  Which is, strangely enough, not the element of the toughest character in ATLA through ATLK-- Toph.

[img]http://avatarthelastairbenderonline.com/wp-content/uploads/2010/10/ep57-440-300x200.png[/img]

Oh, wait...

EDIT:  Ah-crap..  someone got there first XD  'Till next time, perhaps.